Clinical Application Study Of Magnetic Resonance Enterography And Radiomics In Evaluating Crohn’s Disease Activity

Part Ⅰ: Development and Validation of Magnetic Resonance Optimized Index of Activity in Crohn’s Disease Objectives: This study aimed to develop a simple and accurate magnetic resonance regression model based on magnetic resonance enterography to assess crohn’s disease activity.Materials and Methods: 65 patients with crohn’s disease who underwent colonoscopy and magnetic resonance enterography were retrospectively analyzed.The subjects were divided into non-mild and moderate-severe activity group with Simple endoscopic score for Crohn’s disease(SES-CD)as the reference standard.Logistic regression analysis was applied to determine the magnetic resonance imaging indexes independently associated with SES-CD,and develop a new magnetic regression model.We compared the diagnostic efficacy of the new MR regression model with that of the traditional Ma RIA(Magnetic Resonance Index of Activity)model,and we validated the responsiveness and reliability of the magnetic resonance enterography regression model in an independent cohort of 12 patients.Results: Logistic regression analysis showed that bowel wall thickness,bowel wall relative edema and ADC value were independently correlated with SES-CD score.We use these factors to establish the Magnetic resonance Optimized Index of activity(MROIA).When the MROIA score was greater than 3,the area under the curve(AUC)for differentiating non-mild CD activity from moderate to severe CD activity was 0.901(95% confidence interval:0.824-0.952,P < 0.01),sensitivity was 84.78%,specificity was 84.62%.Delong test showed no significant difference in AUC between MROIA and Ma RIA(Z = 0.493,P = 0.062).In addition,MROIA and SES-CD had a good correlation in the diagnosis of disease activity(r=0.725,P < 0.01).Internal validation showed that in patients with moderate-severe CD,the post-treatment MROIA score of ulcerated intestinal segments was significantly lower than the pre-treatment score(P < 0.01).Conclusions: MROIA is an effective tool for objective evaluation of patients with CD.Its calculation process is relatively simple and its diagnostic efficiency is high.It may become a non-invasive method for endoscopic evaluation of ileocolonic Crohn’s disease.Part Ⅱ: Prediction of Intestinal Crohn’s Disease activity Based on MRE ImagingObjective: This study aimed to investigate the diagnostic efficacy of contrast enhanced magnetic resonance enterography in the diagnosis of activity of the small intestine in Crohn’s disease.Methods: 82 Crohn’s disease patients with terminal ileal involvement who were divided into the non-mild and the moderate-severe activity group according to the the magnetic resonance activity index(Ma RIA)were retrospectively analyzed.ITK-SNAP was used to delineate the regions of interest on the delayed enhanced MR images,and Py Radiomics software was used to extract features of ROI.Then Fe Ature Explorer Pro was used to randomly divide extracted features into training set and test set in a ratio of 7:3(training set: 58,31/27=positive/negative;test set: 24,13/11= positive/negative),select feature and develop model.The radiomics model was applied to the test set for validation.Finally,we used the receiver operating characteristic curve to evaluate the diagnostic efficacy of the radiomics model for distinguishing non-mild and moderate-severe activities in CD.Results: A total of 374 features were extracted from the delayed enhanced MR enterography images.In Fe Ature Explorer Pro,after feature selection,the final three features were incorporated into the radiomics model,as shown below: Radscore = 1.248×wavelet-HLL＿firstorder＿Kurtosis + 0.717 × wavelet-LLL＿first order＿90Percentile + 1.116×wavelet-LLL＿glcm＿Joint Average.The diagnostic efficacy of the radiomics model for non-mild activity and moderate-severe activity was 0.953,sensitivity: 90.3%,specificity: 88.9%,[95%CI:(0.8949-0.9938)] in the training set,and 0.881,sensitivity: 84.6%,specificity: 81.2%,[95%CI:(0.7109-0.9926)] in the test set.Conclusion: The radiomics model based on contrast-enhanced magnetic resonance enterography(MRE)is effective in the diagnosis of activity of the small intestine in crohn’s disease.